How do I cheaply make this area look nicer?

It will be easier with a 5l sprayer @Friendly, it's easy to target accurately with the attachment and nozzle which you can adjust. The consistency is like water. Trying to paint something with that consistency will be messy and wasteful . I spray my fence whenever necessary without causing any damage to the plants nearby. As a safeguard you could cover the plants with a bin liner or a car boot liner that you get free from garden centres.

 

Patio Magic has worked wonders on my old very green fence, thanks for the tip. It's all ready for painting now!

 

Patio Magic is a miracle in a bottle @Friendly

 

Great, it does work well! Your paint will adhere better now, good luck with it.